Engineers with GovTech Singapore's Data Science and Artificial Intelligence Division have launched a website called Colourise.sg that uses deep learning AI to colorize black and white images. The website doesn't require any technical skills from the user and is free to use. Colorized results are delivered in seconds and, more often than not, are very realistic.

The project was detailed by software engineer Preston Lim, who explained that Colourise.sg was trained specifically to colorize historical black and white Singaporean photos. This differs from some competing AI-based colorizers, Algorithmia being one given example, which are often trained using an image dataset called ImageNet.

Singapore.” The New York Public Library Digital Collections. The Miriam and Ira D. Wallach Division of Art, Prints and Photographs: Picture Collection, The New York Public Library (left), colourised photo by Colourise.sg (right)

The tool remains an excellent option for colorizing images outside of a Singaporean context, however. There are limitations to the tool, primarily that users aren't able to specify the original color of image elements, meaning the final colorized image may be realistic, but not reflect the scene's true colors.

According to the team behind Colourise.sg, the colorizer works best with high-resolution images featuring humans and natural scenery. The system is capable of colorizing images that contain objects it can identify based on the dataset used to train it. In photos that contain objects the AI can't recognize, the results may include unrealistic colors as the system must simply use its best guess.

Several excellent examples of Colourise.sg's capabilities are provided on Medium.